Design of 4-DOF Voice Coil Motor with Function of Reducing Laser Geometrical Fluctuations

In order to improve the quality of the laser and shorten the optical path of the fast steering mirror (FSM) laser compensation system, this paper proposes a four-degrees-of-freedom (4-DOF) voice coil motor (VCM) with the function of reducing laser geometrical fluctuations. The feature of this paper is the combination of a DC brushed spindle motor and the proposed 4-DOF VCM. A diffuser is installed on the shaft of the DC brushed motor for suppressing the laser speckle. The proposed 4-DOF VCM is combined with a laboratory-designed mirror set, controlling the laser direction to compensate for laser fluctuations. The proposed actuator was designed and verified by using the commercial CAD software SolidWorks and finite element analysis (FEA) software ANSYS. A mathematical model was built to simulate the dynamic response of the proposed 4-DOF VCM in MATLAB Simulink.

Experimental Research on the Influence of Working Conditions on Vibration and Temperature Rise of Si3N4 Full-Ceramic Bearing Motors

Working conditions such as lubrication, preload, and rotational speed have important influence on vibration and temperature rise of the spindle motor. In this study, controlled variable experiments are carried out on the silicon nitride (Si3N4) full-ceramic ball bearing and steel bearing of the same type, and the vibration signal characteristics and temperature rise of the spindle motor are tested and analysed, by changing the lubrication conditions, preloads, and rotational speeds of the spindle motor. Through the research, it is found that as the rotational speed increases, the vibration velocity of the Si3N4 full-ceramic bearing spindle motor under different preloads and lubrication conditions shows an overall increasing trend; kurtosis generally presents a downward trend and gradually flattens, indicating that although the vibration velocity increases at high speeds, the vibration signal shows a relatively stable state. As the rotational speed increases, the difference of vibration velocity under the condition of applying preload and no preload decreases, indicating that the influence of preload on the vibration of full-ceramic bearing spindle motor decreases with the increase in rotational speeds. At the same time, it is found that fr and 5fr have greater impact on the vibration of full-ceramic bearing spindle motor, where fr is the frequency of the bearing in normal operation, and 5fr is 5 times of the normal operating frequency. Lubrication conditions have little effect on the temperature rise of full-ceramic bearing spindle motor, and the temperature rise under nonlubricated conditions is even slightly lower than that under grease lubrication conditions. The research results show that the vibration velocity and temperature rise of Si3N4 full-ceramic bearing spindle motor are less than those of steel bearing with the same type, indicating that full-ceramic bearing has better performance than steel bearing under the same working conditions.

On-Board Reagent Storage and Release by Solvent-Selective, Rotationally Opened Membranes – A Digital Twin Approach

Decentralized bioanalytical testing in resource-poor settings ranges among the prime applications of microfluidic systems. The high operational autonomy in such point-of-care / point-of-use scenarios requires on-board stored liquid reagents, which need to be safely contained during long-term storage, transport and handling, and reliably released prior to activation. Over the recent decades, centrifugal microfluidic technologies have demonstrated the capability of integrated, automated and parallelized sample preparation and detection of bioanalytical protocols. This paper introduces a novel concept for onboard storage of liquid reagents which can be delivered in a well-defined manner by a rotational stimulus of the system-innate spindle motor, while still aligning with the conceptual simplicity of such “Lab-on-a-Disc” (LoaD) concepts. The reagent storage technology is captured by a digital twin which allows making complex performance analysis and algorithmic design optimization according to given objectives as expressed by target metrics.

A Fast Engineering Method for Estimating Iron Losses in Induction Type Motor Spindles Based on Equivalent Magnetic Circuit

The iron losses in the motor of motorized spindles have a significant effect on the heat generation, working efficiency, and speed-torque characteristics of motorized spindles as well as on their thermal deformation and machining accuracy. The existing finite element and analytical methods based on Maxwell’s equations are too complicated to be suitable for engineering designers. A fast engineering method for estimating iron losses in the spindle motor is presented based on equivalent magnetic circuit (EMC) where the problem of solving a complex electromagnetic field inside the spindle motor is simplified into a simple magnetic circuit calculation by the assumption that the magnetic flux density distribution of any cross section along the magnetic flux direction in the spindle motor is uniform. The EMC is combined with the Boglietti’s model. They are integrated into a developed program by compiling source codes to achieve the analysis and prediction of iron losses in the spindle motor. The results obtained from the proposed method are compared with the prototype experiment data to verify its validity. With the purpose of ensuring accurate experiment results of iron losses, a method of no load running combined with a sudden loss of power supply is proposed to eliminate the braking torque and electromagnetic losses of the spindle motor, namely to achieve the separation of the mechanical loss from the total losses.

Тhe operability analysis of spindle-motor hybrid electromechanical systems

Motor-spindles are belong to a special class of complex dynamic systems of natural and natural-anthropogenic origin, which can be realized both translational and rotational motion, and represent a variety of developing species. Such systems are used in metalworking complexes, lathes, milling, drilling, grinding, multi-purpose and other machines. In modern designs of spindle units rolling bearings, hydrostatic, hydrodynamic, gas-static (aerostatic), gas-dynamic (aerodynamic), magnetic bearings and their combinations (hybrids) are used, for example, gas-magnetic (gas-static bearings with a magnetic suspension that allows to provide rotational frequencies) up to 10-20 thousand rpm, and in drilling and milling and grinding up to 100-200 thousand rpm and above. With the further development of technology in the machine-building industry, motor-spindles began to appear, which are able to realize the movement of the feed by means of gears and couplings, using pneumatic systems. They are also able to realize the movement of in using hydraulic systems, using screw gears. The design concepts of hybrid and combined the motor spindles, received by results of structural anticipation on the basis of use of innovative synthesis methods of hybrid electromechanical systems are considered. Results of mechanical calculations of rigidity and electromagnetic calculations are presented in the article. On the ground of the calculation data the operability analysis of the electromechanical systems of motor spindles is made. To develop a morphological model, functional features were selected, which are systematized and divided into three groups in accordance with the modular principle.

Rancang Bangun Acrylic Engraver and Cutting Machine Menggunakan CNC Milling 3 Axis Berbasis Mikrokontroler

<p><em><span lang="EN-US">The purpose of this research is to design and implement an automatic acrylic carving and cutting tool using a microcontroller-based 3-axis CNC machine. Computer Numerical Control (CNC) is a machine technology that is operated automatically to support the demand for a product that has a complex shape and high accuracy. In general, the construction of a 3-axis CNC machine and its working system is synchronization between the computer and its mechanics. This tool has a work process by utilizing the G-Code method as a command on the machine to carry out engraving and cutting automatically. The G-code was obtained from a previously designed image and then converted using the Aspire 9.0 software. Engraving and cutting is done by sending the G-code file to the microcontroller via the Universal G-code Sender software, then the microcontroller sends a signal to drive the motor driver which then drives the stepper motor so that the actuator movement is generated according to the image in the G-code file. Simultaneously the spindle motor will be active to engrave or cut acrylic. In this study, a trial scenario was carried out to determine the precision and accuracy of the tool, namely by engraving and cutting flat shapes such as squares, circles, triangles and segments. The percentage of success generated from this tool is 97,08% to 100%. Furthermore, testing is carried out to make products in the form of engraving writing, logos and calligraphy. Apart from that, we also tested cutting letters and key chains. When the test is carried out, the accuracy level is 1mm. </span></em></p>

Oversizing Thread Diagnosis in Tapping Operation

Automotive, railway and aerospace sectors require a high level of quality on the thread profiles in their manufacturing systems knowing that the tapping process is a complex manufacturing process and the last operation in a manufacturing cell. Therefore, a multivariate statistical process control chart, for each tap, is presented based on the principal components of the torque signal directly measured from spindle motor drive to diagnosis the thread profile quality. This on-line multivariate control chart has implemented an alarm to avoid defected screw threads (oversized). Therefore, it could work automatically without any operator intervention assessing the thread quality and the safety is guaranteed during the tapping process.